An image detector can be configured to receive and convert light reflected from an object, after being emitted from a light source, into one or more color channel signals. The color channel signal(s) can be used to define image data that can then be used to produce one or more images of the object on a display. For example, a full-color image of the object can be produced when the object is illuminated by a white light source. Many consumer products, such as video cameras and digital cameras, have imaging systems with this capability.
If a narrow-band light source is used to illuminate an object, a narrowband image can be produced. This can be referred to as narrow-band imaging. A narrow-band light source is a light source associated with a narrow spectrum of electromagnetic radiation compared to a spectrum of electromagnetic radiation associated with a wide-band light source. Imaging using a wide-band light source can be referred to as wide-band imaging. In some applications, a narrow-band light source can be used to illuminate an object so that a narrow-band image that enhances specific features of the object can be produced. For example, a red color light source can be used with an endoscopic system to help medical practitioners readily identify certain tissue structures that are enhanced when illuminated by the red color light.
In some applications, both narrow-band imaging and wide-band imaging are desired. Because known imaging system do not produce images associated with a spectrum of light that is broader than the spectrum of light emitted by the light source, often two different light sources are used in these systems-a narrow-band light source and a wide-band light source. For example, known image processing systems are not capable of producing full-color images when the only light source included in the system is a red color light source. Thus, a need exists for methods and apparatus for defining wide-band image data based on narrow-band image data especially in applications where using a narrow-band light source is desirable.